GameActivity: Remove onOptionsItemSelected and NavUtils import
activity_game.xml: Change RelativeLayout to LinearLayout
Grid: Initiate array with 'height' rows and 'width' columns
grid_element_text_view.xml: In TextView, make sure text is aligned in the center and that it is not selectable
activity_new_game_preferences.xml: Remove XML namespace info from lower level elements
activity_game.xml: Add GridView to represent game grid
GameActivity: Instead of creating a new GridView, set properties for Gridview defined in layout
Grid: Make gameGrid a single dimensional array and change type to Integer[]
GameActivity.onCreate: Fix bug when creating new grid - swapped width and height parameters by mistake